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Tag Archives: PV solar

Cities and renewable energy

By Dave Elliott 

Urban areas account for around 75% of the world’s energy use and there are ambitious plans to reduce their reliance on fossil fuels. Around the world, cities are beginning to think in terms of meeting their energy needs from renewable sources, so as to limit air pollution and climate change problems.  The case for this transition is strong, not least given the likely rise in air-conditioning demand as climate change impacts more,  and there have been many interesting initiatives launched around the world, often led by city governments.  (more…)

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Renewables continue to boom globally

By Dave Elliott

BP says renewables have shown ‘a quicker pace of penetration than any other fuel source in modern history’, and their strong growth meant that they ‘accounted for all of the increase in global power generation in 2015’. BP’s latest review of world energy trends carbon notes that wind power capacity grew by 17.4% and solar by 32.6% last year, with China overtaking Germany and the US as the largest solar generator: www.bp.com/en/global/corporate/energy-economics/statistical-review-of-world-energy.html  REN21 has come up with equally high figures. And looking to the future, both see renewables booming, as does Bloomberg.

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PV solar: big isn’t always better

By Dave Elliott

PV solar is now big – with 227GW installed around the world. But large solar farms apart,  much of it is in small roof-top units. Would bigger arrays be better? Certainly economies of scale suggest large-scale projects are generally more cost-effective than small ones. That holds up well for wind, but does it also hold for PV solar?

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All Energy: an ecumenical approach

By Dave Elliott

The All Energy Conference in Scotland, despite its title, usually focuses on renewables but, some feel provocatively, it has of late also included sessions on nuclear. A petition was raised against this, with over 1,700 signatories, but an ecumenical approach does have its attractions – we get to hear from all the contenders and can form an impression of the overall state of play. Better surely than a partisan ‘no platform’ stance?

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UK Renewable Investment – the right priorities?

by Dave Elliott

The share of renewables in UK electricity supply reached a high of 23.5% in the third quarter of 2015 (Q3), up 5.9% from 2014 Q3, and it seems likely to continue to grow as more projects come on line. However there are some problems. UK investment in renewables reached around £14bn in 2015, but has focused increasingly on the more costly offshore wind option: £8bn was invested in it in 2015. With the government block on support for cheaper on-shore wind and its slowdown of PV solar support, that arguably imbalanced pattern will get worse. It means less capacity per £ invested. Bloomberg forecast that over the next 5 years the UK will in effect lose at least 1 GW of renewable capacity. As offshore wind moves down its cost-reduction curve, the situation may improve, if then the money saved can be spent on other projects, but Bloomberg says ‘without some form of change in policy support, we could see investment drop off a cliff after 2019′. www.independent.co.uk/news/uk/home-news/britains-renewable-energy-industry-is-about-to-fall-off-a-cliff-says-new-research-a6818186.html  (more…)

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PV solar in Germany: too much of a good thing?

By Dave Elliott

An interesting study from the German Development Institute (DIE) of Germany’s ambitious green energy policy asks whether its support for PV solar, and its subsequent rapid expansion, has been a good idea. PV has expanded to over 38GW to almost match wind, now at 40GW, but it has been a costly exercise, since PV was much more expensive than wind. As a result PV has received the lion’s share of support, up to 3 times more than wind, in part since it expanded under the Feed-in Tariff much faster than expected. And although its costs have dropped dramatically, it is still getting proportionately more of the subsidy. Too much some say.

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Goodbye to FiTs

By Dave Elliott

A shift away from Feed-in Tariffs (FiTs) to project auctions as a way to support renewable energy seems to be underway across the EU. The UK government certainly has cut FiT levels and recently warned that the FiT system might be wound up entirely – and soon. Although it seems to have won a last minute partial reprieve, with the level of cuts being reduced from 87% to 64%, after something of an outcry, it is just a matter of time before it goes. Is this a good idea?

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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

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Eco-footprints and technological change

By Dave Elliott

In their paper ‘A system of systems approach to energy sustainability assessment: are all renewables really green?’ Saeed Hadian (UCLA) and Kaveh Madani (ICL), take a comprehensive look at energy system carbon footprints, water footprints, land footprints and costs. They conclude that geothermal energy has the lowest impact, biomass elephant grass the most. As you might expect, coal and oil are also high, wind and solar thermal low, but so is nuclear, while PV solar comes out quite high – more than hydro, or gas: www.sciencedirect.com/science/article/pii/S1470160X14005640 – cor0005

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Which support systems work best?

By Dave Elliott

Renewable energy technologies have required subsidies to help them get established in markets dominated by sometimes cheaper but also often well-supported conventional energy sources – fossil and nuclear also enjoy subsidies. Essentially the renewable subsidies seek to reflect their environmental benefits – something that conventional markets do not internalise. However there are various ways in which subsidies can be applied and some work better than others. (more…)

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