Shortly before his death in 1931, US electricity pioneer Thomas Edison confided to his close friends: "I'd put my money on the sun and solar energy. What a source of power! I hope we don't have to wait until oil and coal run out before we tackle that."
Today, some 90 years later, the pressing global crisis is that we are producing greenhouse gas emissions far more quickly than the biosphere can absorb them. The dramatic rise of renewables in response to this crux mean Edison’s bet on solar may at last be borne out, albeit not for the reasons he expected.
All pathways to maintaining global temperatures below the 1.5 and 2 degree thresholds of dangerous perturbation of the climate system require rapid society-wide decarbonisation, beginning with our energy systems.
Ireland has made impressive strides in this direction, with some 42 per cent of total electrical production last year from renewables, which in our case is overwhelmingly onshore wind energy.
According to the Sustainable Energy Authority, renewables in Irish electricity production reduced CO2 emissions by 4.8 million tonnes in 2019, avoiding nearly €300 million in imported fossil fuels in the process.
Wind energy has come of age in Ireland over the past two decades, with total installed capacity of just over 4,350 megawatts (MW) at the end of 2020. In sharp contrast, solar energy has been the Cinderella sector, with a negligible 50-60 MW of installed capacity – the second lowest in the EU.
The United Kingdom, enjoying almost identical conditions for solar production as Ireland, has, in response to clear government policy and supports, already deployed some 13,500 MW of solar capacity, and it now provides some five per cent of the UK's total year-round electrical requirements.
Belfast not Dublin?
"It has been difficult to explain that solar panels work in Belfast, but somehow not in Dublin," according to Dr Sarah McCormack, associate professor of environmental engineering at Trinity College Dublin (TCD).
She admits that, up until very recently, it was nigh-on impossible to attract much interest – or funding – around solar projects in Ireland. “The general attitude we encountered is that renewable energy is all about wind and ocean power in Ireland, the mindset was that we’re not sunny enough for solar power”. This, as the UK experience has shown, is a significant misconception.
To date, funding for the TCD Solar Energy Applications Group, with which Dr McCormack is involved, has come from Europe, including a recent €1.5 million grant to work in diffuse solar energy, which involves maximising the energy that can be extracted from our frequently cloudy skies.
Regular silicon-based solar panels extract energy from sunlight in the visible spectrum. While direct sunshine is a relative rarity in Irish conditions, even on overcast days, there is quite a high level of incoming UV (ultraviolet) radiation. The TCD research group are developing methods of capturing UV light via specialised luminescent dyes and then re-emitting it into the visible range, where it can be converted into electricity.
Today's silicon-based solar cells are typically 20 per cent efficient, while international research in what are known as tandem cells has seen efficiency of solar cells boosted to as high as 47 per cent. While in terms of raw solar energy production it would be hard for more complex solar panels to compete on cost with the cheap imported panels from China, the real advantage in high-performance panels is in locations where space is at a premium.
Ironically, our slow start in embracing solar technology may give Ireland the benefit of “late-mover advantage” in installing new capacity in the 2020s. The cost per MW of solar panels has fallen precipitously over the last decade and more, and is now some 86 per cent lower than in 2009.
According to the International Energy Agency’s 2020 World Energy Outlook, “for projects with low-cost financing that tap high-quality resources, solar PV is now the cheapest source of electricity in history”.
The emergence of solar power as a literal sunrise industry in our energy landscape happened dramatically last August, when Ireland’s first renewable energy auction saw nearly 800MW of solar projects accepted. Not all of these projects will proceed, but at least five projects approved in this auction are being constructed. It is expected that about 600-700 MW of new solar will come on-stream as a result of this renewable energy support scheme (RESS) auction.
Three in five of the 63 successful solar projects in this round are below 5MW. The main reason, according to analysis by IHS Markit, is that generators below 5MW connected to the distribution system in Ireland don’t have to pay system charges for transmission use. About one in 10 new solar projects are large-scale utility projects above 20MW.
Two to four more RESS auctions are due to be held in the near future, with each expected to see similar levels of solar energy being rolled out. "By 2030, we think we can get solar to around 5GW of utility scale installations, and another 1GW of domestic and small scale commercial," according to Conall Bolger, chief executive of the Irish Solar Energy Association (ISEA).
He points out that in 2020, Ireland produced some 12.6 terawatt-hours (TWh) of green energy, mostly from onshore wind. “By 2030, we need to be hitting 30-35 TWh, so we’re aiming to effectively triple current renewable output in just over eight years, and that means we have to go gangbusters,” Bolger adds.
Given its latecomer status to the grid, Irish system planners have, he believes “consistently underestimated how much it could contribute to the grid”. Network connections in Ireland are over-engineered. “We are speccing these connections for a windy, sunny night,” he jokes.
In sunnier Spain, auctions for solar can get it on the grid for about €24 per megawatt-hour; the equivalent cost in Ireland is three times higher, at €73. "The difference in sunshine between Ireland and Spain does not nearly account for this price differential," Bolger notes.
While Ireland is blessed with excellent wind resources, our best locations for wind are remotest from major east coast population centres, and wind is also most effective at night. Solar produces its power in daytime, when demand is greatest, and the best solar sites are close to where electricity demand is highest.
And while onshore wind farms are often opposed by people who regard them as eyesores, a typical solar farm doesn’t involve major construction, operates silently and is all but invisible, even from neighbouring fields.
Given that Ireland’s agriculture sector produces one-third of total national emissions, there is some scope for mitigation of carbon via solar farms, but the challenge, according to a Government source, is that on-farm demand for electricity is relatively low. “For farmers, the key is whether you are getting paid enough and can get a cheap enough grid connection.”
Another option for farmers is to enter long-term leases of land to commercial-scale solar operators, with up to 80 per cent of a given site still available for limited uses, such as grazing sheep. And, unlike other long-term plays such as forestry, it is easily reversible and the land, having been left fallow, is more likely to improve than deteriorate. However, financial uncertainty, including worry over potential losses under the basic payments scheme, means this potential has yet to be fully realised.
Ireland’s 2030 target for electricity production by renewable energy is 70 per cent, and both industry and Government sources are confident this will not just be met but comfortably exceeded, with the prospect of even hitting the 100 per cent mark by then. This even allows for expanding electricity demand from electric vehicles, data centres and heat pumps for zero-carbon home heating.
The sunlit uplands of an energy-independent zero carbon Ireland in the coming decades have never seemed more within reach.
John Gibbons is an environmental journalist and co-author of the Routledge International Handbook of Environmental Journalism