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Improving energy efficiency is one of the easiest and most cost-effective actions that can be taken to reduce global-warming emissions. Increasing efficiency reduces our need for electricity, liquid fuels and gas. It reduces our dependence on oil imports and, importantly, reduces living costs for regular people.

In Hawaii, generous rebates are offered to residents and businesses to encourage the replacement of inefficient appliances, light bulbs, water heaters, and other devices with more energy-efficient ones. This has allowed residents and businesses to reduce their energy consumption and save money.

We can achieve similar results when we optimize the efficiency of our largest ‘appliance’ – our cars. Hawaii’s cars and the rest of our transportation sector account for more than 60% of our greenhouse gas emissions. We burn around 30 million gallons of gasoline every month. And most of this energy is wasted due to serious inefficiencies associated with gasoline and diesel engines.

Many improvements are straightforward and apply to all vehicles, like removing unneeded items from the trunk, driving at appropriate speeds and maintaining tire pressure. These actions help reduce the amount of fuel required to operate the cars and reduce costs and emissions. Other actions, like switching from a gas-powered vehicle to an electric vehicle, can have far bigger impacts.

Buy The Most Efficient Car

There is a wide array of car options today – internal combustion (gas and diesel), hybrid, plug-in hybrid, fuel-cell electric and battery electric.

The most inefficient vehicles are traditional cars with an internal combustion engine. Only 12%-30% of the energy in the fuel used in these cars is used for propulsion. The rest is wasted as heat – around 80% of the energy. Put another way – for every $100 of gasoline, only $12 to $30 of that amount is used to move you around. The rest is wasted.

Hybrids are incrementally better, with the best models achieving about twice the efficiency of a regular car. Hybrids have, in addition to the regular engine, a battery and electric motor to enhance efficiency.

However, the most efficient vehicles are electric, which can be up to five times more efficient than a regular car. There are currently three types of electric vehicles:

• Plug-in Hybrid Electric Vehicles (PHEVs) – electric vehicles that still require fossil fuel – these cars offer limited pure-electric miles and rely on a gas engine to keep the battery charged. Examples include the Kia Niro PHEV, Ford Escape, Honda Clarity, Toyota Prius Prime, and Kia Sorento.
• Fuel Cell Electric Vehicles (FCEVs or “hydrogen vehicles”) – electric vehicles that rely on a fuel-cell to convert hydrogen to electricity. These vehicles include a small battery. Examples include the Toyota Mirai, Honda Clarity, and the Hyundai NEXO.
• Battery Electric Vehicles (BEVs) – the ‘pure’ electric vehicle. These cars include a large battery to store the energy required for long-range driving and rely only on electricity for fuel. BEVs represent the vast majority of EVs on the road today. There is a growing number of EV makes and models — over a will be available by 2023. And BEVs enjoy a steadily growing charging infrastructure and service options. Thanks to ever-evolving battery technology, BEVs are becoming more affordable over time and less reliant on rare metals like cobalt. Examples are Tesla (several models), Chevy Bolt, Nissan LEAF, Kia Niro EV, Ford Mach-e, and the recently-released Rivian R1T.

The BEV is by far the most efficient of these three types of EVs with roughly 73% efficiency versus 22% for the FCEV. The comparisons are summarized well in the first two columns in the following diagram from the nonprofit Transport and Environment’s 2017 report.

Many other reports and publications have found similar results.

The more significant losses associated with FCEVs are mainly due to the inefficiencies related to converting electricity to hydrogen, compression and transportation of the gas, and conversion of the hydrogen back to electricity. The losses are inherently due to basic physics.

A simple way to understand the efficiency differences between BEVs and FCEVs is to compare how far they travel on the same amount of electricity. For a given amount of electricity, a BEV will travel 300 miles for every 100 miles that an FCEV will travel.

The ‘Fueling’ Dilemma

It’s worth noting that around 97% of the hydrogen produced globally comes from methane or coal. Hawaii’s efforts in this space have, thankfully, been mainly focused on green hydrogen produced through mainly renewable energy. The above comparisons are relevant to FCEVs running on green hydrogen.

This is not to suggest that hydrogen vehicles or the fuel-cell platform are not valuable. Despite their inefficiency, they are valuable in applications where heavy transport is needed and gross vehicle weight must be managed, such as transoceanic air transport and possibly long-distance land and ocean freight. The fuel-cell can also offer a compact grid long-term energy storage solution.

Fueling BEVs and FCEVs can be a challenge. BEVs are still at an advantage here. BEVs can be fueled wherever there is an electrical outlet, and many EV owners rely on home charging for most or all of their charging. However, many people, renters, for example, may not have the opportunity to charge at home, so we need to dramatically expand charging infrastructure to support electric car and bus charging.

Hydrogen fueling is virtually nonexistent at this time. There are a couple of fueling stations on Oahu, including one that offers subsidized fueling for Toyota Mirai EVs. On Hawaii Island, a substantial hydrogen production facility exists at NELHA; a smaller one can be found at Blue Planet Energy near Puu Waa Waa.

The NELHA facility will generate hydrogen for three small buses as part of a demonstration project on Hawaii Island. Notably, a hydrogen fueling infrastructure is costly to deploy and dependent on electricity, which is also expensive.

Time Is Running Out

Hawaii has a tremendous opportunity to decarbonize its economy with renewable energy derived from solar, wind, hydro, and geothermal and sustainable transportation. A thoughtful transition of its ground transportation system from one mainly reliant on the passenger car to one that is multimodal (mass transit, micro-mobility, shared transportation) is critical.

A sustainable transportation future maximizes overall efficiency, which means reducing our collective vehicle miles traveled. Minimizing the need for cars is one meaningful way to accomplish this.

Since passenger cars will continue to be relevant, we also need to focus on the most efficient electric vehicles, those readily available, and those that can be serviced and fueled today. Hawaii is making progress on the vehicle electrification front – it is now number two in the nation in EVs per capita. However, EVs still represent only about 2% of the passenger vehicles in Hawaii.

We don’t have much time to achieve the emissions reductions required to contribute to meaningful climate change mitigation. By focusing attention and resources on solutions that are efficient and have the highest likelihood of success today, we can accelerate our transition away from fossil fuels. BEVs are the solution that will allow Hawaii to rapidly decarbonize its ground transportation, maximize its renewable energy, save money, and democratize clean transportation, 

Let’s mobilize our limited resources and focus attention on battery electric vehicles, a sure bet for sustainable transportation in Hawaii. We still have time to heal our planet and ensure a livable world for our keiki and future generations, but we must act with urgency.