The global stock of plug-in electrified vehicles crested past 2 million last year, but there’s still a long way to go, say policymakers and advocates.

In its Global EV Outlook 2017, the International Energy Agency documented the total number of plug-in hybrids and all-electric cars as picking up pace since hitting 1 million in 2015.

This report, while making waves now, follows a report broke in January.

SEE ALSO: The World Just Bought Its Two-Millionth Plug-in Car

Counting vehicles where possible back to 2005, the IEA noted 95 percent of sales are clustered in 10 countries.

The U.S. held the lead until 2015, but as has been documented here before, China now leads the way.

So far, battery electric vehicle (BEV) uptake has been consistently ahead of the uptake of plug-in hybrid electric vehicles (PHEVs). The IEA notes: “The electric car stock shown here is primarily estimated on the basis of cumulative sales since 2005. When available, stock numbers from official national statistics have been used, provided good consistency with sales evolutions.”

“China became the country with the largest electric car stock, with about a third of the global total,” said the IEA of the 2015 takeover of the lead. “With more than 200 million electric two-wheelers, 3 to 4 million low-speed electric vehicles (LSEVs) and more than 300,000 electric buses, China is also by far the global leader in the electrification of other transport modes.”

As for infrastructure, this too is on the increase, but the rate of increase is not as fast as prior years.

“In 2016, the annual growth rate of publicly available charging (72%) was higher, but of a similar magnitude, than the electric car stock growth rate in the same year (60%),” said the agency. “Despite a continuous and impressive increase in the electric car stock, electric vehicle supply equipment (EVSE) deployment and electric car sales in the past five years, annual growth rates have been declining.”

Just a Start

The global stock of plug-in vehicles is now only 0.2 percent of all light-duty passenger vehicles, and the IEA projects 300 times the current volume of PEVs is needed over the next 23 years.

“In order to limit temperature increases to below 2 degrees Celsius by the end of the century, the number of electric cars will need to reach 600 million by 2040,” said the IEA.

The agency added chances are good the global stock of plug-in vehicles could rise to 9 million to as much as 20 million by 2020, and between 40 and 70 million by 2025.

The chief impediment to faster growth is the cost of batteries, says the agency, which while declining markedly this decade, have still represented a barrier to achieving price-for-performance parity with petroleum-powered vehicles.

Deployment scenarios for the stock of plug-in electrified cars to 2030. The IEA says: “The level of ambition resulting from the OEM announcements assessed here shows a fairly good alignment with country targets to 2020. To 2025, the range estimated suggests that OEM ambitions lie within the range corresponding to the Reference Technology Scenario (RTS) and 2DS projections from the IEA, broadly matching the Paris Declaration on Electro-Mobility and Climate Change and Call to Action (Paris Declaration).”

At least that is the mainstream view, and the proof offered is the slow acceptance rate, but a closer look reveals plug-in electrified cars can already make good economic sense, particularly when coupled with incentives and factoring low energy and operating costs.

Advocates are quick to point out the value of plug-in cars can be realized by consumers today – using the same evidence that the market has started, and people who’ve jumped into the waters have found out the benefits are there.

But perceptions have warned off many would-be buyers, and facts remain the sticker prices of EVs and plug-in hybrids remain comparably higher than gas and diesel powered vehicles.

Until fully perceived price parity between internal combustion and electrified vehicles is realized, the IEA recommends a continuation of tax incentives, exemptions, and other perks continue.

And while it is not a major concern today, the IEA foresees issues with the grid being overloaded in regions unprepared.

“EV charging could also have a sizeable impact on the loads applied to the grid at certain times and locations, with consequences for adequacy and quality of power supply, the risk of cost increases for consumers and negative feedback on transport electrification prospects,” said the agency. “EVSE deployment needs to be conceived in a way that handles these risks and takes advantage of the options available for mitigating these impacts.”

Full IEA report