(Bloomberg) -- If you assessed the future of energy based on how it’s depicted in images — rows of solar panels, fields with wind turbines, big blocks of batteries — you could be forgiven for forgetting about all the cables.  

But it would be a big omission, because cables are the backbone  of the electric grid. In many cases, building a grid that can take on all those renewables can be more expensive than the cost of the solar and wind farms themselves.

Consider the UK. Bound by a climate law that calls for reaching net-zero emissions by 2050, the country is on a spree to build as much 50 GW of offshore wind power by 2030. That would more than triple current capacity at a cost of about £120 billion ($139 billion).  

In July, the country’s grid put out a plan to spend £54 billion to ensure that all offshore wind capacity can actually be used. Half the money would go toward building infrastructure to link up turbines that are hundreds of miles out at sea, with the rest to ensure that the new power supply reaches the people who need it. In other words: cables.  

“No one really talks about the grid. It’s a little bit boring to most people. They don't understand it or get it,” says Keith Anderson, chief executive officer of Scottish Power, a division of renewable power giant Iberdrola SA. “You want net zero? You need the grid. You want offshore wind? You need the grid. You want electric cars? You need the grid.”

The UK isn’t alone. China’s State Grid Corp. aims to spend $350 billion through 2025 on upgrades to increase the transmission of renewable power. The US will need to spend $200 billion on cables to meet 2030 climate goals, while it spends about $360 billion on clean-power generation. Overall, the International Energy Agency says global investment in power grids would need to hit $820 billion per year by 2030, up from about $260 billion in 2020, to get on track to limit global warming to 1.5° Celsius.

These spending plans represent a shift in energy-transition strategy from relying predominantly on renewable sources of power. For the most part, new solar farms and wind parks have just been added to the existing grid, but scaling up these technologies to the level needed to prevent the worst impacts of climate change will require a network built to maximize renewable-energy deployment. And while it’s true that, at the point of generation, solar and wind power are already vastly cheaper than fossil fuels, projections about their increasing affordability often fail to include the anticipated cost of grid infrastructure.

“Grid buildout is an essential tool to facilitate decarbonization,” said Will Gorman, researcher at  Lawrence Berkeley National Laboratory. “Transmission is going to be a key piece of the puzzle when talking about high penetration of renewables on the grid.”

To see that dynamic at work, you can look to Texas, which developed what are known as “competitive renewable energy zones” to build out transmission that would connect some of the state’s best wind resources to population centers that needed it. As a result, Texas has become one of the world’s biggest sources of wind power globally. If it were a country, the state would have the fifth largest fleet of wind farms in the world.

At the same time, Texas is an example of grids’ limits. The state has no links to power networks in other states, meaning it can’t export electricity when generation exceeds demand, or import from other places that have different wind and solar resources. 

That shortfall also highlights one of the biggest impediments to grid expansion: the priorities of local politicians and communities. Leaders in Texas don’t want to join up with other grids because of the federal oversight that would come as a side effect. 

The UK is facing a different kind of local opposition. Coastal populations are happy with wind turbines far out at sea, but don’t want the cable infrastructure required to bring the power to shore near them. That means taking a longer route to land the cables where there aren’t people.

One of the surest ways to cut emissions, energy use and energy bills is to electrify as much of our economy as possible, while cleaning up the grid. All that, however, depends critically on no longer ignoring the grid itself. 

©2022 Bloomberg L.P.