* Host of COP26 climate talks aims for greener, affordable heat
* Air-source and water-source heat from the River Clyde a focus
* Revamped historic tenements and social housing could be a model
By Sonia Elks
GLASGOW, Scotland, Sept 9 (Thomson Reuters Foundation) - W hen her first electricity bill arrived, Hollie Osborne's dream of a "forever home" for herself and her two-year-old son began to fade.
Her flat in a new social housing development, built in a handsome red-brick former school in Glasgow, represented a chance for the single mother to rebuild her life, after struggling with serious mental health issues.
But as the harsh Scottish winter set in, the heating needed to be on constantly to stay warm - and the 150-pound ($200) monthly bills that began arriving represented half her income.
I was having to bring my boy in bed beside me, just because I couldn't afford to put the heating on," Osborne said.
"It's meant to be my forever home with my child - and I can't afford to live here now."
A spokesperson for the Home Group Scotland housing association that owns and manages the property said it was working to resolve issues with heating in some flats and offering support to tenants who had received high bills.
Several miles up the road, Tizo Seleman, 40, and his partner Saada Mwalimu, both care workers who live with their baby daughter in a high-rise block in Glasgow's northern Springburn district, expect their once-onerous heating bills to shrink.
In July, their inefficient old heaters were replaced with a low-carbon air-source heat pump system - part of a bid by their social housing landlord to make heat cheaper for tenants and slash climate-changing emissions.
"I think it will make a real difference – I will get some savings," predicted Seleman.
In cities around the world, making existing homes more energy efficient and switching them to run on green power is a big challenge as the world tries to slash carbon emissions.
Glasgow, a former industrial hub that will host the key COP26 U.N. climate negotiations this November, is one of those trying to drive the shift as part of the C40 Cities network, a group of nearly 100 major cities worldwide working for faster action on climate change.
The cities have each committed to delivering climate action plans designed to spur uptake of clean energy, boost adaptation to climate threats and turn the Paris Agreement into a reality.
In Glasgow, which has pledged to reach net-zero emissions by 2030, that includes pulling water-source heat from the city's river, improving public transport and planting more urban trees.
It also is working to find ways to make homes climate-smart, comfortable and cheaper to heat while ensuring those least able to afford the green shift are not left out.
That is not an easy job in a port city noted for its winter cold, where around a quarter of residents pay more than 10% of their income for heat and restrictions on how historic homes can be modified make retrofits challenging.
"If people are left behind, then it's not going to tackle emissions," said James Roberts of Living Rent, a renters' union which works with low- and middle-income people.
About 15% of Scotland's emissions come from heating homes, which makes finding low-carbon ways to keep families warm a priority as Britain aims to slash its emissions by 78% by 2035.
"It is one of our biggest climate justice issues," Susan Aitken, leader of Glasgow City Council, told the Thomson Reuters Foundation.
The council wants to ensure efforts to decarbonise also speed up "the way in which we are addressing some of these long-standing social and economic inequalities", she added.
HEAT VERSUS HERITAGE
While Glasgow looks to the future, its streets are largely shaped by its past.
The city is known for its sweeping terraces of red and blonde sandstone tenements – properties built in the late 19th and early 20th centuries that contain multiple flats and make up about a fifth of Glasgow's homes, according to the council.
The tenements - beloved for their high ceilings, original fireplaces and other features - are also considered chilly and sometimes damp, while their stonework and historic features make efficiency upgrades more challenging.
But one inner-city project aims to produce a blueprint for revamping them to modern energy efficiency standards without losing their character.
An eight-flat tenement in Glasgow's southern Govanhill district has been stripped back to its bare bones for a deep retrofit. The work includes new insulation for walls, floors and the roof, plus triple-glazed windows and air-source heat pumps.
The retrofit aims to reduce energy bills for homeowners by up to 90%. How the building functions will be monitored by researchers, with data used to inform future tenement upgrades.
"This is the first of its kind. That's why it's exciting - but it's also challenging," said Drew Carr from John Gilbert Architects, which is leading work for the Southside Housing Association.
As Glasgow looks for new green energy sources, it is turning in part to the wide Clyde River that winds through its centre.
In much the same way as air-source heat devices work, large water-source heat pumps could draw residual heat from the Clyde, which is then piped to homes and businesses, providing a lower-carbon alternative to traditional heating systems.
This method could meet half the city's total heating demand, estimates social enterprise Greenspace Scotland, which is running a project to explore how urban green spaces and water can provide low-carbon energy.
The river is already fuelling one district heat network serving homes and businesses just outside Glasgow, and another planned system will power a high-tech 'innovation district' in the centre.
One catch is that although renewable systems can compete on price with heat produced from fossil-fuel electricity, the gas boilers that still warm most homes remain even cheaper.
Largely thanks to plentiful fracking supplies, fossil-fuel gas costs about 3 pence per kilowatt-hour (kWh) compared to an average of about 17 pence for electricity, said John Maslen of Greenspace Scotland.
Ensuring a switch away from gas to meet climate change goals does not increase fuel poverty might require a major subsidy scheme for poorer households, he added.
As leaders prepare to gather at the COP26 talks in Glasgow to hammer out rules designed to ramp up emissions cuts, one crucial question will be how to finance it all.
"The huge issue with a 'just transition' and retrofitting is who's going to pay?" said Michael Mikulewicz, a researcher at the Centre for Climate Justice at Glasgow Caledonian University.
Glasgow City Council leader Aitken said reaching the city's aim of net-zero emissions by 2030 is likely to require about 30 billion pounds ($41 billion) of investment, including 5 billion pounds just to retrofit homes to higher efficiency standards.
"Governments alone can't deliver this. We need to have private investment come in," she said.
The city will launch an investment prospectus around the time of the COP26 conference, laying out 10 major projects.
Glasgow will work to make the voices of city leaders heard at the summit, she said, calling cities crucial players in the race to reach net-zero goals.
"Cities are where most of the emissions are generated because it's where most of the people are - but it's also where you get the biggest gains in decarbonisation most quickly," she added.
($1 = 0.7190 pounds)
(Reporting by Sonia Elks @soniaelks; Additional reporting by Amber Milne; Editing by Laurie Goering and Megan Rowling. Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers the lives of people around the world who struggle to live freely or fairly. Visit http://news.trust.org)
Our Standards: The Thomson Reuters Trust Principles.