Heat solutions via renewable energy

Heat solutions via renewable energy

As the benefits of renewable energy production and usage can now be seen throughout the country further advancements are required in order fully utilise the potential that we have. Whilst renewable energy is clean and does not require a traditional fuel supply its generation can be intermittent. Although this is not so bad as some have us believe there are solutions which can increase renewable energy’s usage at times when the sources are not generating as much as is being demanded.

The first of these is energy storage which we have discussed previously.  However last week a new report commissioned by Scottish Renewables explored the potential market opportunities for energy storage in the UK.

The report makes a number of recommendations for developing energy storage technologies as well as tackling the primary risk holding back a country wide roll out of energy storage in this country, a constant and reliable revenue stream.

The report “Cracking the code: A guide to energy storage revenue streams and how to de-risk them” was compiled and written by Everoze with assistance from RES and the University of Strathclyde’s Power Networks Demonstration Centre included the following recommendations; (1) long contracts from National Grid to help get the banks on board, (2) revenue streams designed to enable them to be stacked together easily addressing the revenue interface risk, (3) creating new revenue opportunities within the distribution network, (4) the introduction of a cap and floor mechanism for storage assets with long lifetimes, something which is already in place to support similar investments in other countries, and (5) the reduction of revenue risk which in turn will help deliver the £2.4billion of consumer savings previously highlighted by DECC.

Jenny Hogan, Director of Policy at industry body Scottish Renewables speaking at the report launch said “Energy storage is an essential part of the transition to a cleaner energy mix, for delivering an energy system for the 21st century and for reaching our climate change targets.

“While batteries today are 94% cheaper than they were in 1990, and a range of pumped storage projects are ‘shovel-ready’ or in the planning process, the current market arrangements are at risk of favouring more expensive sources of flexibility for our network.

“These range from ensuring that service contracts are procured in a way that supports investment in low-cost technologies, through to encouraging aggregators to ensure that people already deploying in storage in their homes are able to realise the full benefits it can bring.”

Felicity Jones, partner at Everoze, also speaking at the launch added “If the overwhelming challenge for the solar and wind sector has been cost reduction, the key challenge for storage is getting financiers comfortable with the merchant risk of revenue streams.

“Yes, continued reduction in the capital cost of storage is needed, but the bigger challenge lies elsewhere. Renewables developers eyeing up storage must flip their attention from cost to the other half of the profit formula: revenue.”

Another solution proposed to increase renewable generation and usage at first raises eyebrows and brings up a whole raft of safety questions. When you speak of hydrogen people’s first thoughts tend to be “isn’t that highly flammable?” It has been almost 80 years since the Hindenburg disaster, most of us weren’t even alive when it happened but even to today it inspires the negatively associate with hydrogen.

However over the past two years a team of scientists have been testing how dangerous it would be to run the UK’s gas network on hydrogen as opposed to natural gas.

At present natural gas heats approximately 80% of UK households. It is composed mainly of methane, a hydrocarbon, which when burned produces carbon dioxide a greenhouse gas which aids in global warning.

Under the Climate Change Act the UK is required to cut its greenhouse gas emissions to 1990 level by 2050 and the domestic use of natural gas is one of the largest contributors of our emissions and decarbonising heat one of our biggest challenges.

Most solutions have so far consists of different ways of electrifying heat that is replacing gas boilers with heat pumps or a direct heating system. However former Shadow Energy Minister Alan Whitehead casts doubt on such a plan being sustainable for all housing.

“As far as customers are concerned, that does mean, among other things, ripping out all their boilers, ripping out the mains, and replacing those with heat pumps. I would predict that pretty much every customer would regard that transition with some horror.”

Iain Conn, chief executive of British Gas owner Centrica, agreed “We pay 5p/kwh for gas, and 15p/kwh for electricity – so this whole idea of electrifying everything is mad, especially when we have got natural gas plumbed into all of the homes and if you electrify everything, what are you going to generate the electricity from?”

Both offered an alternative which would mean rather than changing the system would involve changing the gas.

Whitehead added “Rather than ripping everything out can we supply, for example, green gas, or different forms of gas supply into the system? Leaving it substantially as it is but actually changing the carbonisation mix of what goes into it – and giving the customer a much better deal.”

The greenest gas option would be pure hydrogen which burns cleanly and produces only heat and water. Plus hydrogen could be produced via electrolysis using renewable energy during periods of higher generation but lower usage. A water source would be required but since the burning process produces water there would be no overall negative effect.

So brings us back to the potential danger and the recent tests carried out. Mark Crowther, technical director at Kiwa Gastec who carried out the testing said “Gas leaks are rare, but do occur from time to time from sources as diverse as a defective gas appliance to DIY accidents.”

“The project was designed to prove whether accidental leaks from a pure hydrogen, or hydrogen and natural gas mixture supply, would have more or less risk attached than a leak from a natural gas supply.”

The testing showed that since hydrogen is much lighter than natural gas it was less likely than natural gas to accumulate in dangerous amounts. Also while hydrogen is odourless this could be countered by artificially adding odour as is done to natural gas.

“Overall it would appear hydrogen is of about the same risk as mains gas,” Crowther stated. “Because of this, and its zero carbon footprint in the grand scheme of things its widespread use will almost certainly be safer for the future of mankind.”

The key to this is that the hydrogen could be delivered via the current gas network infrastructure. Central heating systems would remain mostly intact although new boilers (at a cost of about £3,000 each) would need to be installed. Estimated costs are therefore about £2 billion per large city.

Dan Sadler, who ran the H21 study for NGN and is currently seconded to the energy department said “Whatever we do it’s going to cost a lot of money. The alternative is we get 90pc of people in cities who use gas for their heating to convert to electric, and we then have to rebuild all the electrical infrastructure.”

However Professor Jim Skea, a member of the Committee on Climate Change remains sceptical stating “I don’t think we have found in our analysis that using hydrogen networks for residential heating is necessarily the most cost effective way to do things.”

The Committee on Climate Change believes that heat pumps and district heating systems are less costly way of achieving this but that means a sharp increase in electricity generation. If this is to be achieved while complying with the Climate Change Act this will have to be generated from renewable sources in vast quantities and stored for usage in high peak periods which brings us full circle.

Either way renewable energy must play a major role in heating us whilst at the same time vastly reducing our carbon emission levels. Whichever method wins out will be dependent on market forces but regardless we have to ensure that it does happen.


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