Which will have the most impact?

Tap a card below to make your choice.
Tap ‘Read more’ to explore a solution.

Try another one

District Heating

Buildings and Cities

With district systems, a central plant channels hot and/or cool water via a network of pipes to many buildings — heating and cooling them more efficiently.

Read more

Rank and results by 2050 #27

District Heating

Reduced CO2: 9 gigatons
Net cost (Billions US$): $457.10
Net operational savings: $3,543.50 billion
What do these numbers mean?

TOTAL CO2-EQ REDUCTION (GT)

Total CO2-equivalent reduction in atmospheric greenhouse gases by 2050 (gigatons)

NET COST (billions US $)

Net cost to implement

SAVINGS (billions US $)

Net savings by 2050

Impact:

By replacing existing stand-alone water- and space-heating systems, district heating can reduce carbon dioxide emissions by 9.4 gigatons by 2050 and save $3.5 trillion in energy costs. Our analysis estimates current adoption at .01 percent of heating demand, growing to 10 percent over the next thirty years. While natural gas is currently the most prevalent fuel source for district heating facilities, we model the impact only of alternative sources such as geothermal and solar thermal energy that will become more prevalent over time.

District Heating

Buildings and Cities

With district systems, a central plant channels hot and/or cool water via a network of pipes to many buildings — heating and cooling them more efficiently.

In district heating and cooling (DHC) systems, a central plant channels hot and/or cool water via a network of underground pipes to many buildings. Heat exchangers and heat pumps separate buildings from the distribution network, so that heating and cooling are centralized while thermostats remain independent. Rather than having small boilers and chilling units whir away at each structure, DHC provides thermal energy collectively—and more efficiently.

Copenhagen, Denmark, is the global standout in DHC. It now meets 98 percent of heating demand with the world’s largest district system, fueled with waste heat from coal-fired power plants and waste-to-energy plants. (In the coming years, biomass will replace all coal use.) Since 2010, Copenhagen has also tapped the waters of the Øresund Strait for district cooling.

Compared to individual heating and cooling systems, Tokyo’s district system cuts energy use and carbon dioxide emissions in half—a powerful example of DHC’s potential. Although a tried and tested technology, it is still new and unfamiliar in many parts of the world, and high up-front costs and system complexity continue to be obstacles. Municipal governments play the most essential role in taking this solution to scale.

Vs

Bioplastic

Materials

Ninety percent of plastics could be derived from plants instead of fossil fuels. Bioplastics can be biodegradable and often have lower emissions.

Read more

Rank and results by 2050 #47

Bioplastic

Reduced CO2: 4 gigatons
Net cost (Billions US$): $19.15
What do these numbers mean?

TOTAL CO2-EQ REDUCTION (GT)

Total CO2-equivalent reduction in atmospheric greenhouse gases by 2050 (gigatons)

NET COST (billions US $)

Net cost to implement

SAVINGS (billions US $)

Net savings by 2050

Impact:

We estimate the total production of plastics to grow from 311 million tons in 2014 to at least 792 million tons by 2050. This is conservative, with other sources estimating over 1 billion tons if trends continue. We model the aggressive growth of bioplastics to capture 49 percent of the market by 2050, avoiding 4.3 gigatons of emissions. While technical potential is even higher, this solution is constrained by limited biomass feedstock available without additional land conversion. The cost to produce bioplastics in this scenario is $19 billion over thirty years. While the financial costs are currently higher for producers, they are dropping quickly.

Bioplastic

Materials

Ninety percent of plastics could be derived from plants instead of fossil fuels. Bioplastics can be biodegradable and often have lower emissions.

Globally, we produce roughly 310 million tons of plastic each year. Almost all of it is petro-plastic, made from fossil fuels. Experts, however, estimate that 90 percent of current plastics could be derived from plants instead. Bio-based plastics come from the earth, and those that are biodegradable can return to it—often with lower carbon emissions.

What affords plastics their malleability are chainlike polymers, comprised of many atoms or molecules bound to one another. Cellulose, the most abundant organic material on earth, is a polymer in the cell walls of plants. Chitin is another abundant polymer, found in the shells and exoskeletons of crustaceans and insects. Potatoes, sugarcane, tree bark, algae, and shrimp all contain natural polymers that can be converted to plastic.

Most bioplastics are used in packaging, but they are finding their way into everything from textiles to pharmaceuticals to electronics. Research continues to push the bounds of feedstocks, formulations, and applications. Bioplastics can sequester carbon, especially when made from waste biomass. The big challenge for bioplastics is separation from other waste and appropriate processing. Otherwise, they do not fulfill their promise as more sustainable materials.

Start again