This site uses cookies. By continuing to use this site you agree to our use of cookies. To find out more, see our Privacy and Cookies policy.
Skip to the content

[IOP] A community website from IOP Publishing

Tag Archives: electricity

Transitional green power issues- sectorial conflicts

By Dave Elliott

It is often said that, whereas it should be possible to meet electricity needs from renewables, heating was harder and transport harder still. While wind and solar and other renewables can generate electricity, replacing the use of fossil plants, heating and vehicle transport use of fossil fuels are harder to replace. Except possibly by the use of renewable electricity. Although some disagree, there should be enough renewable electricity output to meet all energy needs in time. However, even enthusiasts accept that there may not be enough to go around initially. So there may be sectorial conflicts at some stages.

(more…)

Posted in Renew your energy | Tagged , , , , , | Leave a comment | Permalink
View all posts by this author  | View this author's profile

Renewable capacity growth continues

by Dave Elliott

REN 21’s annual Renewable Energy Global Status report for 2017 shows continued progress in new capacity installation. Renewable power generating capacity saw its largest annual increase ever in 2016, with an estimated 161 GW of capacity added. Total global renewable capacity was up nearly 9% compared to 2015, to almost 2,017 GW at year’s end, with a rise in renewable electricity generation from 23.7% in 2015 to 24.5% in 2016. Crucially, the world continued to add more renewable power capacity annually than it added (net) capacity from all fossil fuels combined, with wind and PV growing at 4.7%, faster than demand at 2% p.a. Wind reached 487 GW, PV solar 300 GW, with energy storage rising to 156 GW, most of that being pumped hydro but with 1.7 GW of batteries. (more…)

Posted in Renew your energy | Tagged , , , | Leave a comment | Permalink
View all posts by this author  | View this author's profile

What a waste: an end of year lament

By Dave Elliott

In a post-Xmas pre-new year Scrooge-type austerity mood, I worry about the money we are wasting on energy. If you look at Sankey diagrams of energy flows from primary resources to final end use, you will see that for many countries around half the raw energy input is wasted in the conversion process, most of it being rejected into the atmosphere as heat, for example from steam-based fossil and nuclear generation systems.

(more…)

Posted in General, Renew your energy | Tagged , , , , , , | Leave a comment | Permalink
View all posts by this author  | View this author's profile

Greenpeace 2030 UK energy scenario

By Dave Elliott

85% of UK electric power could be supplied from renewables and low carbon sources by 2030, says a report for Greenpeace, produced by Demand Energy Equality.org. Basically it looks at a Greenpeace high renewables 2030 supply scenario to see if it can meet demand over the year, given demand peaks and weather changes – it uses 11 years of hourly weather data. And crucially it tests whether it is possible to meet a large part of the heat demand from renewable electricity, given that ‘even modest levels of heat electrification result in large increases in peak electrical demand’. It concludes that it is, but that this will only be possible if domestic heat demand is reduced dramatically, by near 60%. That is seen as vital since ‘electrification increases the size of demand peaks on the electricity network; while decarbonisation (via renewables) in turn decreases the predictability of supply intended to meet those (now increased) peaks’. And so ‘if electricity is the medium by which a reliable and clean energy future is to be delivered, then heating demand reduction must be achieved alongside heating electrification’. www.demandenergyequality.org/2030-energy-scenario.html

On the supply side it sees wind energy growing from 13 GW to 77 GW, 55 GW offshore, 22 GW onshore, with PV solar rising from 5 GW to 28 GW. There is also 8 GW of tidal, some biogas use (but no biomass imports), including around 20 GW of local CHP (fired with gas and some biomass), but no new nuclear and no CCS, just around 20 GW of gas CCGT and some demand side management (DSM), to help with balancing. However, interestingly, domestic DSM only ‘plays a modest role in mitigating periods of deficit. Fewer than 7 periods in which total demand shifting exceeds 3 GW occur on average each year’. That is partly because DSM is as yet in its infancy and the report focuses on established technology. But it does report some interesting DSM developments in the industrial sector – where Flexitricity is the first and largest UK provider of national supply-demand balancing services. http://www.flexitricity.com

However it notes the technical, administrative and logistical feasibility of interacting with corporate and large scale power users in this way has not been matched, thus far, in a domestic setting’. That would require National Grid to negotiate contracts to provide demand reduction at peak times with every UK household, and communicate directly with each when needed. Smart meters might allow that, but are still in their trial phase, with many issues to be resolved.

You could say the same of the electric heat pumps that the report seems to see as a key domestic heat supply option; only meeting 25% of the heat demand, not the 90% envisaged in the DECC 2050 High Renewables modeling, but still a lot more than now. Why not also look at green gas for heating (including biogas and Power to Gas conversion) and to the gas grid for supply? It’s already there, with much more capacity than the power grid! While the report does propose some CHP (oddly seen as inflexible) for heat and power, there’s no mention of solar heating and large community-scaled heat stores (as used now in Denmark), and overall it seems overly focused on electricity.

Rather than offering a clever way to balance surpluses from variable renewables, by being able to ramp down power production and ramp up heat production for storage, for use when heat demand was high, CHP is simply seen as producing too much heat in summer. So there is only around 20 GW of CHP included, compared to over 52 GW in the recent Transition Pathways’ Thousand Flowers scenario. And, on the issue of the inevitable occasional electricity surpluses from its large variable renewable capacity, rather than portraying this as a problem, why didn’t it look more to Power to Gas (P2G) to turn it into a solution – making green gas for grid balancing as well as for heating and transport use? It only talks of using P2G hydrogen for vehicles. And why not look to 2-way supergrid links for balancing? As it is, ‘exports only occur once any surpluses have been utilised to the greatest possible extent domestically’, with the level of interconnector exchanges seen as only around 12 TWh p.a. That seems odd, since there is a lot more excess available (apparently near 43 TWh on average) and there may be times when exports of surplus can earn a lot of money, and be more useful/valuable than P2G conversion or other types of storage, helping to balance the cost of importing more when needed at other times. DECC’s 2050 pathway had 30 TWh of imports/exports. It’s a little odd that supergrid links are left to one side, playing a relatively small role in this study, since an earlier Greenpeace report talked them up as a key EU balancing option: http://www.energynautics.com/news/#GP_EU 

Trying to get to 80% renewables by 2030 is pretty demanding. The Pugwash high renewables pathway, on which I worked two years back, only reached around 80% by 2050, pushing it quite hard, with around 100 GW of wind and 35 GW each of PV and tidal: http://britishpugwash.org/pathways-to-2050-three-possible-uk-energy-strategies/ However, that excluded nuclear, long gone by 2050, had 70 TWh p.a of supergrid imports/exports, and only looked to 40% energy savings. By contrast, the new 2030 Greenpeace scenario still retains some left-over nuclear (Sizewell B) and goes for much higher levels of energy saving – and by 2030. That’s a bit of a stretch. It’s akin to the Centre for Alternative Technology’s pioneering Zero Carbon Britain 2030 scenario and adding to the list of challenging and visionary high renewables scenarios: http://zerocarbonbritain.org/ready-for-zero

What it adds in particular is an interesting and helpful test of the operational viability of an ambitious energy mix, although, sadly, it does not provide an economic analysis, arguing that costs are changing too fast to make that useful. While that may be true (and the report does present some examples of falling costs), the absence of full costing may weaken the impact of the analysis – just at the point when the falling cost of renewables ought to be giving them a better chance. Even so, it’s a welcome addition to the pile of studies making the case for renewables, with balancing, as a technically and operationally viable set of options.

* Economic and financial support issues are to the fore in a new global Greenpeace scenario, which I will review shortly. It looks to getting 100% of all energy from renewables by 2050, at no extra net cost, given the fuel cost savings: http://www.greenpeace.org/international/Global/international/publications/climate/2015/Energy-Revolution-2015-Full.pdf

Posted in Renew your energy | Tagged , , , , , | Leave a comment | Permalink
View all posts by this author  | View this author's profile

Plenty of renewables – and they can be balanced

By Dave Elliott

Is there enough renewable energy to meet global needs and can the use of variable sources be effectively balanced?  Recent reports say yes on both counts. In terms of the total resource, a GIS-based study of land/sea use/availability has put the total 2070 global potential for renewable electricity at up to 3,810 EJ, led by solar PV, with about a third of the PV being on buildings. The total estimated resource was roughly in line with most other global renewable studies, like that from the IPCC, and well above likely total global electricity demand, put at around 400 EJ: www.sciencedirect.com/science/article/pii/S0959378015000072 (more…)

Posted in Renew your energy | Tagged , , , , , , , | Leave a comment | Permalink
View all posts by this author  | View this author's profile

Burning Answer

By Dave Elliott

In his powerful and eloquent new book, The Burning Answer, which seems to be a response to Mike Berners-Lee’s book on climate change, The Burning Question, Imperial College Professor of Physics Keith Barnham contends that, despite our much higher energy demands now than in earlier periods of human evolution, our sun can provide all our primary energy needs again. Solar technology can save us from the threats of global warming, diminishing oil resources and nuclear disaster, if we take the necessary action.

(more…)

Posted in Renew your energy | Tagged , , , , , , , , | Leave a comment | Permalink
View all posts by this author  | View this author's profile

Green energy for Africa

By Dave Elliott

The International Renewable Energy Agency says that Africa has the potential and the ability to utilise its renewable resources to fuel the majority of its future growth with renewable energy. It adds ‘doing so would be economically competitive with other solutions, would unlock economies of scale, and would offer substantial benefits in terms of equitable development, local value creation, energy security, and environmental sustainability’.

That seems a bold claim both technologically and economically, and also politically. But the renewable resource is very large (for solar especially) and the technologies are getting cheaper fast. However, with 54 very unevenly developed countries on the huge continent, whether the political and institutional cohesion is there for a co-ordinate push is  less certain. (more…)

Posted in Renew your energy | Tagged , , , , , , , , , | 2 Comments | Permalink
View all posts by this author  | View this author's profile

Smart meters and smart grids

By Dave Elliott

The newly emerging energy system will need new grids of various types. In my previous two posts I looked at international low-loss High Voltage Direct Current supergrids, and suggested that though they may well be developed in the years ahead, the process could be uneven and incremental, starting with local/national smart grids designed to aid local balancing of variable supply and demand. (more…)

Posted in Renew your energy | Tagged , , , , , , , | Leave a comment | Permalink
View all posts by this author  | View this author's profile

Supergrid (2) – could it work?

By Dave Elliott

In my previous post I looked at the potential and problems of supergrids. The basic idea is that, since, in various parts of the EU, there will be times when there is excess electricity generated from wind etc. over and above local demand, this excess can be shunted to regions which are short and have high demand, using low-loss HVDC supergrids. Would it work on a large scale?

(more…)

Posted in Renew your energy | Tagged , , , | Leave a comment | Permalink
View all posts by this author  | View this author's profile

Green pricing issues – how long can a few carry all?

One of my earlier posts discussed how Austin Energy, the #1 US utility in selling renewable electricity, had posted a price for its latest GreenChoice batch of renewable electricity such that it was too high for any more takers. The major issue coming to the fore is that at some point, a small percentage of residential and commercial customers cannot pull along an entire city, much less a state or a country, toward high percentages of renewable energy all by themselves.

In trying to find a way to meet its goals, Austin Energy changed its standard 10-year fixed price (at 9.5 cents/kWh for GreenChoice charge + a standard 3.6 cents/kWh) offer for renewable energy by adding a 5-yr option as well (at 8.0 cents/kWh for GreenChoice charge + a standard 3.6 cents/kWh). Now, after no one is buying the latest batch of green pricing, the charged price has now come under scrutiny by some local experts, saying that in fact Austin Energy is not open enough about how it calculates this price. So in attempting to come to a solution, a task force has been set up to come up with a solution. Additionally, Austin Energy is now proposing charging 5.7 cents/kWh and a 5-yr fixed price for the Green Choice charge.

A local paper covered the issue well, see this Austin Chronicle article. Also see a website, PowerSmack, organized by a local energy consultant to discuss these issues.

Much of the consternation over the price for the green electricity stems from the electric grid transmission charges that are applied to much of the wind power coming from West Texas through a limited set of transmission lines. The state of Texas has a plan in motion to build more transmission lines to relieve this congestion, but the solution is 4-5 years out during the siting and construction of the transmission lines. So, we wait for the transmission lines, but this is not a unique problem, and further expansion of renewable energy in Texas and other locations will face similar issues. Even with the transmission constraint charges, reports are showing that overall electricity prices in Texas are actually lower

But as Austin Energy general manager Roger Duncan states in the Austin Chronicle article and in regard to the GreenChoice program, it was intended to stimulate the market for renewables and not continue forever. The city council of Austin (who officially approves pricing for electricity that Austin Energy) is now coming to grips with the unavoidable fact that to meet goals for low carbon emissions (and we really haven’t even started) and high percentages of renewable electricity, sooner or later everyone must contribute in one form or another. These levels of contribution by poor, middle class, rich, environmentalists, industrialists, greenies, turquoisers, left, right, up, down and everything in between is what the future is all about. The future is being determined on a local level by a small group of people representing just under 1 million citizens in Austin, TX USA, and perhaps on a global level this December in Copenhagen by thousands of world representatives representing almost every country in the world.

Posted in Energy the nexus of everything | Tagged , , , | Leave a comment | Permalink
View all posts by this author  | View this author's profile